JP3121065B2 - camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera, and more particularly to an exposure control device for a camera capable of switching the size of a photographing screen on a film.

[0002]

2. Description of the Related Art In recent years, there have been proposed a large number of cameras that can switch the size of a photographing screen.
In addition, products of various specifications have come to be marketed. The photographing screen size switching camera disclosed in Japanese Patent Application No. 3-200877 proposed by the present applicant has a film loaded from the size, length, DX code, or the like of a film cartridge. It is determined whether the screen is for screen photographing, and the screen mask for determining the photographed screen size is moved according to the judgment to switch the screen size. By using this camera, a larger photographing screen or a higher quality print can be obtained even for a film having the same external width.

On the other hand, in recent years, it has become possible to divide the light quantity distribution on the screen and perform photometry, to automatically perform exposure correction, and to set the degree of importance for the pattern photometry value of each area in the screen. Cameras provided with such photometric devices have come to be widely used. Above in-pattern metering device incorporated in a conventional camera, for example, have a photometric device comprising a light receiving element divided image of the subject is projected
And it is, 3 for metering on the photometric pattern shown in FIG. 17
The pattern photometric outputs of the two light receiving elements are converted to digital signals. The average subject brightness is calculated in consideration of the degree of emphasis on each pattern photometry output, and an exposure value is calculated from the average brightness. Based on the calculated exposure value, an exposure control unit including a shutter unit and the like controls exposure control. Is performed. Japanese Patent Application Laid-Open No. 61-295534 discloses a pseudo hope.
The exposure control in the far camera is shown. this
Camera masks part of the shooting screen for pseudo telephoto
At that time, the mass is also placed in front of the photometric element.
King to reduce the effect of light outside the shooting range during pseudo telephoto.
I'm frustrated.

[0004]

Considering a camera in which the above-mentioned conventional pattern photometric device is incorporated in the camera for switching the photographic screen size, if the focal length of the photographic lens is constant, the angle of glare of the photometric element is also constant. is there. However,
When the size of the shooting screen is changed, a normal size screen (hereinafter referred to as N) with a normal size of 35 mm in FIG.
On the Gn, the photometric patterns Pa, Pb,
17B, on the enlarged size screen (hereinafter, referred to as B screen) Gb of FIG.
a ′, Pb ′, Pc ′, and the ratio of the occupied area of the photometric pattern to the photographing screen is relatively reduced by the enlargement of the screen. For this reason, when comparing the pictures of the N screen and the B screen photographed with exactly the same framing with each size set, the difference in the photometric characteristics of the weighting ratio indicating the degree of importance to the photometric value of each photometric pattern at the time of photography is different. As a result, the exposure condition of the finally printed note trimming photograph differs.

For example, if the output of the central photometric pattern Pa is lower than the output of the peripheral photometric pattern Pb by a certain value or more as an automatic backlight compensation, an algorithm for performing positive correction to prevent the central subject from being blackened. It is assumed that photometric processing is performed by At this time, the backlit subject having the size of the photometric pattern Pa at the time of the N-screen shooting is protruded into the area of the photometric pattern Pb 'if the same framing is performed at the time of the B-screen shooting. On the other hand, a backlit subject having the size of the light metering pattern Pa 'at the time of shooting the B screen becomes smaller than the light metering pattern Pa if the same framing is performed at the time of shooting the N screen. In such a case, even if the difference between the backlit subject and the surrounding brightness is at the backlight determination level, the brightness difference between the two patterns may be reduced by switching the screen size, so that the backlight may not be determined as a backlight state.

[0006] In addition, when performing photometry that emphasizes the value of the photometry pattern Pa in the center-weighted photometry mode, it is important to emphasize a relatively narrow range when shooting the B screen rather than when shooting the N screen. become. FIG. 18 is a diagram showing a photometric characteristic diagram showing a change in a weighting ratio K indicating a degree of importance of a photometric value of a photometric pattern in each photographing screen size in the center-weighted photometric mode. In the figure, the left side from the optical axis shows a photometric characteristic line KL1 of the weighting ratio K with respect to the photometric patterns Pa to Pc between the optical axis O and the screen edge GT in the screen at the time of N-screen shooting. On the right side of the optical axis, the photometric patterns Pa 'to Pc' between the optical axis O and the screen edge GT 'on the screen at the time of shooting the B screen are shown.
2 shows a photometric characteristic line KL2 of the weighting ratio K with respect to.
Then, when performing exposure control, a weighting coefficient for multiplying each photometric value by the photometric value of each photometric pattern is determined based on the above-mentioned weighting ratio corresponding to the pattern. An exposure value is obtained from the weighted average luminance L obtained from the weighting coefficient and each photometric value, and exposure control is performed. For example, the photometric value of the photometric pattern Pa to Pc La, Lb, and Lc, the weighted ratio Ka indicating the value level of each of the photometry values, Kb, as K c, weighting coefficients that are determined from their weight ratios K1, K2, K3 Accordingly, the weighted average luminance L is represented by the following equation. That is, L = K1 × La + K2 × Lb + K3 × Lc (1) However, the weighting factors K1, K2, K3 are represented by the following equations.

K1 = Ka / (Ka + Kb + Kc) (2) K2 = Kb / (Ka + Kb + Kc) (3) K3 = Kc / (Ka + Kb + Kc) (4) The characteristic line KL1 'on the right side of FIG. 18 is a line that shows the characteristic line KL1 at the time of photographing the N screen as a symmetric shape for comparison.

As can be seen from FIG. 18, since the screen size is widened in the B screen, the width of the photometric pattern in the center-weighted portion is relatively narrow with respect to the screen edge GT ', and the characteristic line KL2 is different from the characteristic line KL1. Is also sharpened, resulting in a difference between the two photometric characteristics. If the photographer is familiar with the photometric characteristics of the camera as the ratio of the range that can be seen in the viewfinder of the camera in N-screen shooting, when trying to execute B-screen shooting, the above-described N-screen shooting and B-screen shooting will be described. Such a difference in the photometric characteristics causes a problem that an exposure value different from an intended exposure value is calculated.

Further, in a case where an exposure value is calculated using a plurality of light receiving elements, switching of a screen size causes
Since the ratio of each pattern to the entire screen is substantially changed, the same configuration and the same algorithm may cause loss of the same exposure calculation characteristic in the exposure value calculation when the screen size is changed. is there. Further, in the case where a masking member is placed in front of the photometric element as in JP-A-61-295534, it is necessary to newly provide a masking member. When the masking member is an LCD, an LCD element and an electric circuit for driving the LCD element are required. Further, when the masking member is a mechanical light shielding material, there is a problem that a light shielding material and a mechanical mechanism for moving the light shielding material from the normal position to the mask position are required. In recent years, photometric elements have become extremely small, and it is very difficult to accurately mask such photometric elements. The present invention has been made in order to solve the above-described problem, and even if the photographing screen size is changed, the photographer has the same exposure characteristics.
You can shoot with a sense, and you will lose the will and familiarity of the photographer
It is an object of the present invention to provide a camera that does not cause a problem.

[0010]

A first camera according to the present invention comprises: a photographing screen size input means for instructing a change of a photographing screen size; a plurality of light receiving elements for measuring light in different regions in the photographing region; Exposure calculation means for performing an exposure calculation in consideration of a weighting coefficient with respect to the output of the light receiving element, and a characteristic diagram approximated by a step change of the weighting coefficient corresponding to the plurality of light receiving elements. A weighting factor for output values of the plurality of light receiving elements is changed so that a shape from the center of the screen to an edge of the screen is equal before and after the screen size is changed. And Further, the second camera according to the present invention includes a photographing screen size input unit for instructing a change of a photographing screen size, a plurality of light receiving elements for measuring light in different areas in the photographing area, and a selection from the plurality of light receiving elements. Exposure calculation means for performing an exposure calculation based on the output thus obtained, wherein the ratio of the dimensional ratio of the light receiving element selected from the center of the screen to the edge of the screen before the screen size is changed. The selection of the plurality of light receiving elements is changed so as to be equal after the screen size is changed.

Another one of the cameras according to the present invention is a photographing screen size input means for instructing a change of the photographing screen size,
A metering means having a plurality of light receiving elements for metering different areas of the photographing region, which includes the exposure calculation unit that performs exposure calculation based on the output of the photometric means, the screen rhinoceros
Screen before and after changing the screen size.
The selection of the plurality of light receiving elements is changed so that the photometric distribution characteristic curve from the center of the surface to the edge of the screen is substantially the same.

[0012]

[0013]

In one of the above cameras, when the size of the photographing screen is changed , the photometric distribution characteristics in the screen become substantially the same.
Weighting the photometric values obtained from the plurality of light receiving elements
Change the coefficient to determine the exposure value. Also, in another of the above cameras, when the shooting screen size is changed,
In order to make the photometric distribution characteristics in the screen substantially the same,
An exposure value is determined by selecting a light receiving element.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a block diagram showing an electric circuit of a photometric device incorporated in a camera according to a first embodiment of the present invention. This camera, said a normal size of the N screen size screen switch shooting camera capable of shooting captured and expanded B screen size, further, by the photometric device, row physician photometry on the photometric pattern In response to the switching of the photographing screen, the average brightness is obtained based on a weighting coefficient obtained from an appropriate weighting ratio indicating the degree of importance, and exposure control is performed.

The photometric device is disposed on a finder optical system 30 (see FIG. 5) of the camera, as shown in FIG. 1, and is a photometric device. , 3 light-receiving elements 1a, 1b, and 1c, amplifying circuits 2a, 2b, and 2c for amplifying the light-metering output of each of the light-receiving elements, and an A / D that performs A / D conversion.
A conversion circuit 3 and an exposure calculating unit 4 which is an exposure calculating means and calculates an exposure value based on the A / D converted photometric output
And exposure control is performed based on the exposure value, and is configured by an exposure control unit 5 including a shutter unit and the like. In addition, the above three first, second,
The three light receiving elements 1a, 1b, and 1c, for example, measure the light of a subject image on the light measurement patterns Pa, Pb, and Pc shown in FIG.

FIGS. 2 and 3 are a front view and a rear view, respectively, of the camera according to the present embodiment with the rear cover removed. As shown in FIG. 2, a photographing lens 12, a zooming operation switch button 11, an objective lens 33 of a finder optical system 30, a size switching switch button 13 between an N screen and a B screen, and the like are provided on the front surface of the main body 10 of the camera. Are arranged. A release button 16 is provided on the upper left side. The photographing lens 12 is set to have such a size that its image circle can correspond to the screen B. Then, as shown in FIG. 3, on the rear lid side of the camera, the eyepiece 34 of the finder optical system 30, a mask opening 14 corresponding to the screen B in the center, a shutter 15,
A patrone loading chamber 17 and a film winding chamber 29 are arranged on both sides of the mask opening 14. The film take-up chamber 18 is provided in the film take-up chamber 29.
And a pressing roller 19 for pressing the film and reliably winding the film. Further, the camera body 10
A photographing mask switching mechanism 20, which is a changing means for switching the photographing mask between the N screen and the B screen, is incorporated therein, and the photographing screen size is determined by the positions of the mask frames 27 and 28 driven by the mechanism. .

FIG. 4 shows the photographing screen mask switching mechanism 2.
FIG. 2 is a diagram showing a configuration of a zero. This mask switching mechanism 20
Is disposed in the camera body 10 as described above,
B screen and N by the operation of the screen size switching motor 21
The size of the photographing mask with respect to the screen is switched.
The rotation of the screen size switching motor 21 is controlled by an instruction from a system controller (not shown) in accordance with the operation of the screen size switching switch button 13. The output gear 2 of the switching motor 21
A pinion 23 is rotatably meshed with the pinion 2, and a pinion 24 is rotatably meshed with the pinion 23. The mask frames 27 and 28 that are switched and driven by the pinions 23 and 24 are formed with L-shaped frame plates facing each other, and are configured to move in a diagonal direction with respect to each other. That is, both end portions of both mask frames 27 and 28 extend diagonally from each other, and racks 27a and 28a are formed at the edge portions extending upward. And both racks 27a, 28a
Are engaged with the pinions 23 and 24, respectively. In addition, guide elongated holes 27b, 2
8b and 27c, 28c are drilled, and the respective guide slots are fitted into guide pins 25, 26 to which the main body is fixed.

The switching operation of the photographing screen mask switching mechanism 20 configured as described above will now be described.
Suppose that it was in the state of FIG. 3 or FIG. In this state, since the mask frames 27 and 28 are retracted outside the mask opening 14 and the photographing screen is masked by the opening 14, the B screen photographing size is set. Therefore, the screen size switching motor 21 is driven by the arrow λ.
1, the pinions 23 and 24 rotate in the directions of arrows λ2 and λ3, respectively, and the racks 27a and 28a of the mask frames 27 and 28 move in the directions of arrows λ4 and λ, respectively.
Move in 5 direction. As a result, the mask frames 27 and 28 move inward from each other to make the inside of the frames smaller, and N
A mask frame 20N having a screen size is formed, and the N-screen shooting is enabled. The screen size switching motor 21
Rotate in the direction opposite to the arrow λ1, the mask frames 27 and 28 move in the opposite direction, that is, the direction in which the inside of the frame becomes larger, and retreat outside the mask opening 14 of the B screen size. The screen B is in the shooting state.

FIG. 5 is a perspective view showing the configuration of the finder optical system 30 capable of changing the size of the field frame. This optical system is mainly composed of a real image type finder optical system composed of an objective lens group 33, an erecting prism 31, and an eyepiece lens group. Field of view 32 for screen
A transmission type liquid crystal plate 32 capable of displaying a and a field frame 32b for N screens is provided so that the field frames can be electrically switched. B of this transmission type liquid crystal plate 32
Field of view 32a for screen shooting and field of view 32 for N screen shooting
The indications b are formed as shown in FIGS. 6A and 6B, respectively. The switching of the display is controlled by the system controller in accordance with the screen size switching operation.

Further, as shown in FIG. 7, a photometric prism 36 is joined to the upper portion 31a of the erecting prism 31, and the photometric element 1 is disposed on the upper surface of the photometric prism 36. The photometric prism 36 and the prism 31
a is formed of the same material, and its joint surface 36a is a half mirror. Since the liquid crystal plate 32 and the photometric element 1 are located at optically conjugate positions with the half mirror interposed therebetween, The real image formed on the plate 32 is the photometric element 1
Also form an image on the light receiving surface of The photometric element 1 includes three first, second, and third light receiving elements 1a, 1b, and 1c as described above.
(A) of FIG.
As shown in (2), photometry is performed on the areas corresponding to the photometry patterns Pa to Pc. However, the angle of view for photometry is the angle of view at the time of shooting the N screen.

Next, the photometric and exposure control operations of the camera of the present embodiment configured as described above will be described with reference to the flowchart of FIG. 8 and the block diagram of FIG. First, a photographing mask is set to a desired screen size by the size switching button 13 in FIG. Then, when the release button 16 is half-pressed to turn on the first release switch, the photometric mode processing starts, and the flow proceeds to step S10.
1 to Step S103, the photometric patterns Pa to P
The photometric outputs of the first, second, and third light receiving elements 1a, 1b, and 1c for c are amplified by the amplifier circuits 2a to 2c and A / D converted by the A / D converter circuit 3. The output is input to the exposure calculation control circuit 4, and is output from step S104 to step S106.
Calculates the luminance La, Lb, Lc of the subject for each of the photometric patterns Pa to Pc. Subsequently, step S1
In steps 07 to S110, weighting is performed on each luminance based on the selected photographing screen size to obtain a weighted average luminance L. That is, it is determined whether the selected shooting screen size is N screen or B screen (step S107).
In the case of the screen, the process proceeds to step S108, and in the case of the B screen, the process proceeds to step S109, in which weighting factors K1 to K3 corresponding to the respective patterns adapted to the respective selected screen sizes are set. Then, in step S110, the luminance value La
To Lc and the weighted coefficients K1 to K3, the weighted average luminance L
Is calculated, and an exposure value is calculated based on the weighted average luminance L in step S111. Subsequently, an exposure based on the exposure value is executed by an ON signal of a second release switch by pressing the release button 16 in two steps, and the present process ends.

Next, a method of calculating the weighted average luminance L will be described in detail with reference to FIG. The present camera is a camera that performs so-called center-weighted average photometry, and has weighting ratios Ka, Kb, and Kc indicating the degree of importance of the photometric patterns Pa to Pc.
Are set to 1, 0.7, and 0.5, respectively. From the weighting ratios, weighting factors K1, K2, and K3 by which actual photometric values are multiplied are obtained by using the above equations (2) to (4). FIG. 9 is a photometric characteristic diagram showing the weighting ratio with respect to the photometric value of the photometric pattern at each photographic screen size of the camera of the present embodiment. As shown in FIG. Characteristic line KL of the change of the weighting ratio K for the photometric patterns Pa to Pc between the optical axis O on the screen and the screen edge GT at the time.
11 is shown. On the right side of the optical axis, the photometric pattern Pa 'between the optical axis O and the screen edge GT' on the screen during B screen shooting
A photometric characteristic line KL22 showing the weighting ratio K to Pc 'is shown. The characteristic line KL11 'on the right is a symmetrical shape of the characteristic line KL11 at the time of photographing N screens for comparison.

In this embodiment, the characteristic line KL2 of the weighting ratio K at the time of photographing the B screen is compared with that at the time of photographing the N screen in the conventional photometric device of the camera as described with reference to FIG. In order to prevent the photometric pattern P from being changed as shown by the photometric characteristic line KL22 of the weighting ratio K in FIG.
The weighting ratio Kb ′ for b ′ is changed from 0.7 to 0.8, and the characteristic line KL22 is changed to the photometric characteristic line KL for N-screen shooting.
Try to get as close as possible to 11. The weight ratios Ka ', Kc' to the other photometric patterns Pa ', Pc'
Is set to 1,0.5 as in the case of N-screen shooting.

When the N-screen is photographed, the weighted average luminance L is calculated using the weighting coefficient obtained from the weighting ratio based on the photometric characteristic line KL11. When the B-screen is photographed, the weighted average luminance L is calculated based on the weighting ratio based on the photometric characteristic line KL22. A weighted average luminance L is calculated using the obtained weighting coefficients, exposure values are obtained, and exposure control is performed. In the weighted average luminance calculation process, as shown in FIG. 9, first, when the set size is N screens, the weight ratios Ka, Kb,
Kc of 1, 0.7, 0.5 is applied as it is, and the weighting coefficients K1, K2, K are obtained from the equations (2), (3), (4).
As 3, K1 = 1 / (1 + 0.7 + 0.5) = 0.455 K2 = 0.7 / (1 + 0.7 + 0.5) = 0.318 K3 = 0.5 / (1 + 0.7 + 0.5) = 0.227 is required. On the other hand, when the set size is the B screen,
The weighting ratios Ka, Kb, and Kc for the B screen are 1, 0.
Applying 8, 0.5, and from the above equations (2), (3), (4), as the weighting coefficients K1, K2, K3, K1 = 1 / (1 + 0.8 + 0.5) = 0.435 K2 = 0.8 / (1 + 0.8 + 0.5) = 0.348 K3 = 0.5 / (1 + 0.8 + 0.5) = 0.217

In the photometric exposure control process of FIG. 8, the above-mentioned weighting factors corresponding to the size of the photographing screen are set in steps S108 and S109. Subsequently, step S11
At 0, a weighted average luminance L is obtained from the pattern photometric values La, Lb, Lc and the weighting coefficients K1, K2, K3 according to the above equation (1). Even a photographer who is accustomed to the center-weighted average metering based on the weighting factor can shoot the B screen with the same feeling.

As described above, in the camera of the present embodiment, the change in the photometric characteristic caused by the change in the size ratio of the photometric pattern to the entire screen due to the change in the screen size is completely changed by changing the above-mentioned addition ratio. Even if the average brightness is calculated by the same algorithm, an extremely close characteristic can be obtained before changing the screen. Therefore, the photographer's intention and familiarity are not spoiled. In this embodiment, the photometric element is 3
Although a divided light receiving element is used, it goes without saying that the number of divisions may be any number, and the weighting ratio is not limited to the above value, but may take a value convenient for photometry.

Next, a camera according to a second embodiment of the present invention will be described. This camera, similar to the camera of the first embodiment, is a camera capable of switching between normal size N screen size shooting and enlarged B screen size shooting, and includes a shooting lens and a viewfinder. An optical system and a photographic mask switching mechanism 20 as a changing means shown in FIG. 4 are incorporated. The photometric device built into this camera also has a photometric element composed of a plurality of light receiving elements. However, the photometric element on each pattern is selected by selecting the above light receiving element in response to switching of the shooting screen. And average brightness is obtained from the selected photometric output.
Exposure control is performed. However, a photometric element 41 (FIG.
As shown in FIG. 10, the layout of the photometric pattern is shown in FIG. 10. The first light receiving element 41d having the photometric pattern Pd at the center of the image frame and the second photodetector pattern Pe disposed outside the photometric pattern Pd. A light receiving element 41e, a third light receiving element 41f having a photometric pattern Pf outside the photometric pattern Pe and corresponding to the N frame outer frame Fn, and a photometric corresponding to the B screen outer frame Fb outside the photometric pattern Pf And a fourth light receiving element 41g having a pattern Pg.
The ratio of the outer diameter of the photometric pattern Pd to the size of Pf is the same as the ratio of the outer diameter of the photometric pattern Pe to the size of Pg.

FIG. 11 is a block diagram of an electric circuit of a photometric device built in the camera. In the photometric device, photometric outputs from the first, second, third, and fourth light receiving elements 41d, 41e, 41f, and 41g on which a subject image is projected are amplified by amplifier circuits 42d, 42e, 42f, and 42g, and A / A It is digitally converted by a D conversion circuit 43 and input to an exposure calculation unit 44 as exposure calculation means. Therefore, performs calculation of the exposure value by selecting the corresponding photometry outputs, based on the exposure value, the exposure control is performed by the configured exposure control unit 45 by the shutter unit and the like.

Next, the light metering and exposure control operations of the camera of the present embodiment configured as described above will be described with reference to the flowchart of FIG. 12 and the light metering patterns of FIGS. First, a photographing mask is set to a desired screen size by a size switching button. Then, when the release button is half-pressed to turn on the first release switch, the photometric mode processing starts. It is determined whether the selected photographing screen size is the N screen or the B screen (step S201). If the screen is the N screen, the process proceeds to step S202, and if the screen is the B screen, the process proceeds to step S206.

In step S202, the photometric outputs of the first to third light receiving elements 41d, 41e, 41f are A / D converted.
Then, the photometric outputs of the second and third light receiving elements 41e and 41f, which are the photometric outputs related to the photometric patterns Pe and Pf, are added (step S203). The luminance L2 for the photometric patterns Pe and Pf is calculated from the added value (Step S).
204). Subsequently, the luminance L1 of the pattern Pd is calculated from the photometric output of the first light receiving element 41d (step S20).
5) Go to step S211. Here, the luminance L1
13A or 13B in FIG.
The pattern Pd (hatched portion) at the center of the screen Gn corresponds. The peripheral portion indicating the luminance L2 is shown in FIG.
The pattern Pe, which is the peripheral portion of the N screen Gn in FIG. 3A or 3B, corresponds to the added portion of the pattern Pf. Here, FIG. 13B is a diagram in which the boundary between the patterns Pe and Pf in FIG. 13A is not shown.
In addition, FIG. 13A shows B outside the N screen Gn.
The pattern Pf for the screen Gb is also indicated by a broken line.

On the other hand, when the operation proceeds to step S206, the photometric outputs of the first to fourth light receiving elements 41d, 41e, 41f, 41g are A / D converted. Then, the photometric patterns Pd and P
photometric output of the first and second light receiving elements 41d and 41e related to e, also adds photometric pattern Pf and Pg regarding the photometric output of the third and fourth light receiving element 41f and 41g respectively (step S207, and, S208). The luminance L1 of the central portion with respect to the photometric patterns Pd and Pe and the luminance L2 of the peripheral portion with respect to the photometric patterns Pf and Pg are calculated from the added value (steps S209 and S21).
0). Then, the process proceeds to step S211. Here, the central part showing the luminance L1 is shown in FIG.
The pattern Pd, which is the center of the B screen Gb in (B), corresponds to the portion to which the pattern Pe (hatched portion) is added,
The peripheral portion indicating the luminance L2 is the pattern Pf which is the peripheral portion of the B screen Gb in FIG. 14 (A) or (B).
And the portion to which the pattern Pg is added corresponds. Incidentally, (B) in FIG. 14 is a diagram did not show the boundaries of the pattern P f and P g of (A). As described above, the luminance L1 at the center and the luminance L2 at the periphery corresponding to each setting screen are obtained.
1 and the luminance L2 and the luminance L1 and the luminance L2 at the time of setting the B screen, without distinguishing between the setting screens.
The luminances L1 and L2 can be used for backlight determination in post-processing and exposure value calculation. Next, in step S211, it is determined whether or not the subject is in a backlight state. This judgment is
The difference between the brightness L1 at the center and the brightness L2 at the periphery is 2Ev
When there is the above, the backlight is determined to be in a backlight state. And
If the luminance difference is less than 2 Ev and the light is not a backlight, the process proceeds to step S212, and the exposure value is calculated from the average value of the luminances L1 and L2 without correction. On the other hand, if it is determined that the subject is backlit, the process proceeds to step S213, and the exposure value obtained from the average value of the luminances L1 and L2 is subjected to plus correction of +1.5 Ev to determine the exposure value. Subsequently, in step S214, the process proceeds to step S215 in response to an ON signal of the second release switch by pressing the release button two steps, performs exposure based on the exposure value, and ends the present process.

Since each pattern size is set to the size described in the pattern layout of FIG.
The ratio of the size of the central pattern (Pd + Pe) to the size of the B screen Gb for B screen shooting in FIG. 14B is the same as the size of the N screen Gn for N screen shooting in FIG. It is equal to the ratio of the size of the central pattern (Pd) to the height. Therefore, in the present embodiment, as described above, the luminance L1 of the central portion and the luminance L2 of the peripheral portion when the N screen is set, and the luminance L1 of the central portion and the luminance L2 of the peripheral portion when the B screen is set are as described above. Without discrimination, it can be used for post-processing backlight determination and exposure value calculation. Then, the processing can be performed in a state where the change in the photometric characteristic due to the screen size switching is eliminated, and the photometric processing with a high degree of identity of the exposure calculation can be performed.

Next, a modification of the photometric device for a camera according to the second embodiment will be described. In the second embodiment, the photometric output of each pattern is subjected to an addition process after A / D conversion, but in this variation, the addition is not performed by calculation, and a predetermined photometric element 41 is selected. This is performed by adding outputs on a circuit. That is, FIG.
FIG. 14 is a block diagram of a photometric device of the present modification. First, an output of a light receiving element 41d is directly connected to an amplifier circuit 47a. The output of the light receiving element 41e is input to the amplifier circuit 47a via the analog switch 46a, and is also input to the amplifier circuit 47b via the analog switch 46b. The output of the light receiving element 41f is
7b. Further, the output of the light receiving element 41g is input to the amplifier circuit 47b via the analog switch 46c. Then, the analog switches 46a to 46c
Is turned on and off in relation to the selection of the screen size. The corresponding photometric pattern of each light receiving element is the same as that of the second embodiment.

The output of the amplifying circuit 47a is used as the value corresponding to the central luminance L1 of the second embodiment.
3 is input. On the other hand, the output of the amplifier circuit 47b is the second
It is input to the A / D conversion circuit 43 as a value corresponding to the peripheral luminance L2 of the embodiment. Subsequently, the calculation of the exposure value and the exposure control are executed based on the central luminance L1 and the peripheral luminance L2 in the same manner as in the second embodiment.

The photometric device according to the present modified example having the above-described configuration is configured such that the analog switch 4
Only 6b is turned on. Then, the output of the light receiving element 41d is fetched from the amplifying circuit 47a as a corresponding value of the center luminance L1. At the same time, the added output of the light receiving elements 41e and 41f is taken in from the amplifier circuit 47b as the corresponding value of the peripheral luminance L2, and the exposure value is calculated. On the other hand, at the time of shooting the B screen, the analog switches 46a and 46c are turned on and the analog switch 46b is turned off. And the light receiving element 41
The sum output of d and 41e is taken in from the amplifying circuit 47a as a corresponding value of the center luminance L1. At the same time, the light receiving element 41f
And 41g are fetched from the amplifying circuit 47b as the corresponding value of the peripheral luminance L2, and the exposure value is calculated. As described above, according to the present modification, the luminance of the central portion and the peripheral portion is obtained by a simple circuit, and it is not necessary to perform the addition operation of the photometric output in the exposure control unit, and the process is simplified.

Next, a camera according to a third embodiment of the present invention will be described. Photometric apparatus of the camera of this embodiment, the change in the ratio to the size image frame of the photometric pattern based on the screen size switching, wherein instead of controlling the electrical output, such as those of the examples, The correction is intended to be performed by changing the angle of view of the plurality of light receiving elements by inserting a correction optical system into a photometric element unit including a plurality of light receiving elements.

FIG. 16 is an arrangement diagram around the photometric element of this embodiment corresponding to the arrangement diagram of the photometric element of the finder optical system of FIG. On the photometric prism 36 having a half mirror portion 36a joined to the erecting prism 31a of the finder optical system, a photometric element 51 which is a photometric means and is composed of a plurality of light receiving elements is provided. The photometric element 51
Are fixed to a rack 54 which is moved in the direction of the incident optical axis by a pinion 55. The converter lens 5 fixed to a rack 56 driven by a pinion 57 is also provided.
2. When the photometric element 51 is retracted to the position 51 ', the photodetector 2 can be inserted into the position 52' above the photometric prism 36. The converter lens 52 is inserted into the position 52 'to change the corresponding angle of view of the light receiving element when the photographing screen size is switched to the B screen, and converts the subject image having a reciprocal magnification of the screen size switching magnification. The image is formed on the light receiving surface of the photometric element 51.

In the camera of the present embodiment configured as described above, the converter lens 52 is at the retracted position when photographing N screens, and each photometric pattern of the photometric element 52 is the same as that of the first embodiment. A subject image in a field frame of N screens is formed on the top. Then, an exposure value is calculated based on the photometric value of each photometric pattern, and exposure control is performed. On the other hand, when the photographing screen size is switched to the B screen, the photometric element 51 retreats to the position 51 'in conjunction with the operation, and the converter lens 52 is inserted into the position 52'. In this state, the field frame of the finder is enlarged for the B screen, but the angle of view of the photometric element 51 is changed by the converter lens 52, the subject image on the photometric element 51 is reduced, and the size of the frame is reduced. The size is the same as the size at the time of shooting the N screen. Then, the ratio of the size of each photometric pattern to the size of the image frame size becomes the same value as the ratio at the time of the N-screen shooting. Therefore, in the present photometric device, the same calculation processing can be used for the exposure value calculation for the N-screen shooting and the B-screen shooting, and the processing in the exposure calculation unit is simplified. However, the converter lens 5
If the light amount of the subject light changes due to 2, the correction calculation is required. In the embodiment described above,
Although the example of switching between the B screen and the N screen has been described,
Not only this but also the top and bottom on the screen
Without changing the so-called panoramic camera or screen aspect ratio
A camera that changes the screen area, so-called pseudo-telephoto shooting
In this case, the same effect can be obtained.

[0039]

As described above , according to the camera of the present invention,
Before changing the screen size, after changing the screen size,
The photometric distribution characteristics from the center of the screen to the edge of the screen.
Characteristics curves so that they are almost the same.
The photographer has the same
Remarkable effect that you can shoot with your senses
You . This is the sensitivity distribution characteristic
If the camera changes, the photographer wants to apply exposure compensation
If you think that the correction amount
The predictive sensation of the photo is not fully utilized
U. Especially for experienced users, "
For those who have exposure compensation because there are bright objects
Becomes a beautiful photo "or" A little more than the center of the screen
The right side is shaded and dark, so it is better to correct this much
The photometry distribution characteristics within the screen.
Curves do not change when screen size is changed
Is a great advantage for photographers. Especially the lab
Reversal film where print correction is not applied
In this case, the effect is most remarkable .

[Brief description of the drawings]

FIG. 1 is a block diagram of a photometric device incorporated in a camera according to a first embodiment of the present invention.

FIG. 2 is a front view of the camera of FIG. 1;

FIG. 3 is a rear view of the camera of FIG. 1 with a rear lid removed.

FIG. 4 is a front view of a photographing screen mask switching mechanism of the camera of FIG. 1;

FIG. 5 is a perspective view of a finder optical system of the camera shown in FIG. 1;

6A and 6B are front views of a liquid crystal display panel of a finder optical system of the camera shown in FIG. 1, wherein FIG. 6A shows a display state at the time of B-screen shooting, and FIG. 6B shows a display state at the time of N-screen shooting. Show.

FIG. 7 is a side view of a photometry unit of the finder optical system of the camera shown in FIG. 1;

FIG. 8 is a flowchart of a photometric exposure control process of the camera of FIG. 1;

FIG. 9 is a photometric characteristic diagram of the photometric device of the camera of FIG. 1;

FIG. 10 is a diagram showing a photometric pattern of a photometric element of a camera according to a second embodiment of the present invention.

FIG. 11 is a block diagram of a photometric device built into the camera of FIG. 10;

FIG. 12 is a flowchart of a photometric exposure control process of the camera of FIG. 10;

13A and 13B are photometric patterns on a photographing screen at the time of photographing N screens of the ten cameras, wherein FIG. 13A is a diagram in which each pattern is distinguished, and FIG. FIG.

14A and 14B are photometric patterns on a photographing screen at the time of photographing the B screen of the above 10 cameras, wherein FIG. 14A is a diagram in which each pattern is distinguished, and FIG. FIG.

FIG. 15 is a block diagram showing a modification of the photometric device of the camera according to the second embodiment.

FIG. 16 is a side view of a photometric unit of a photometric device of a camera, showing a third embodiment of the present invention.

17A and 17B are diagrams showing a photometric pattern for a photographing screen of a conventional camera, wherein FIG. 17A shows a photometric pattern for N-screen photographing, and FIG. 17B shows a photometric pattern for B-screen photographing. .

FIG. 18 is a photometric characteristic diagram of the photometric device of the camera of FIG. 17;

[Explanation of symbols]

1, 41, 51... Photometric elements (photometric means) 1a, 1b, 1c, 41d, 41e, 41f, 41g
………………………………………………………………………………………………………………………………………………………. Exposure calculation unit (exposure calculation means) K1, K2, K3 ................. weighting coefficient

Claims (2)

(57) [Claims] 1. A photographing screen size input means for instructing a change of a photographing screen size, a plurality of light receiving elements for measuring light in different areas in a photographing area, and a weighting factor added to an output of the plurality of light receiving elements. Exposure calculation means for performing an exposure calculation, comprising: a shape from the center of the screen to the edge of the screen of the characteristic diagram approximated by the stepwise change of the weighting coefficient corresponding to the plurality of light receiving elements, A camera, wherein a weighting coefficient for an output value of each of the plurality of light receiving elements is changed so as to be equal before the screen size is changed and after the screen size is changed. 2. A photographing screen size input means for instructing a change of a photographing screen size, a plurality of light receiving elements for measuring light in different areas of the photographing area, and an output selected from the plurality of light receiving elements. Exposure calculation means for performing an exposure calculation, wherein the ratio of the dimensional ratio of the selected light receiving element to the screen from the center of the screen to the edge of the screen is changed from the screen size before the screen size is changed. A camera, wherein the selection of the plurality of light receiving elements is changed so as to be equal afterward.